Method of determining number of repetitions for multiuser broadcast in iot deployments

ABSTRACT

A relay node receives a data block containing multiplexed data streams intended for multiple user equipment (UE) devices being served by the relay node. The relay node extracts the data streams from the data block and allocates them each to a separate narrowband channel that is associated with a particular UE device. The relay node repeatedly transmits the narrowband channels to the UE devices in a broadcast transmission that is transmitted for a predetermined number of repetitions. Each UE device decodes their own respective narrowband channel to obtain the data stream intended for the UE device associated with a particular narrowband channel. A feedback mechanism is utilized by the relay node to determine whether to retransmit a data packet or a new data packet in subsequent broadcast transmissions.

CLAIM OF PRIORITY

The present application claims the benefit of priority to ProvisionalApplication No. 62/661,253, entitled “BROADCAST BASED RELAYING TO THEIOT DEVICES”, docket number TPRO 00321 US, filed Apr. 23, 2018,Provisional Application No. 62/682,081, entitled “CONTROL INFORMATIONFROM MICROCELL TO NODE, MAPPING BLOCKS TO UE ID”, docket number TPRO00322 filed Jun. 7, 2018, Provisional Application No. 62/682,090,entitled “MULTIUSER BROADCAST TRANSMISSION NODE”, docket number TPRO00323 filed Jun. 7, 2018, and Provisional Application No. 62/682,095,entitled “METHOD OF DETERMINING NUMBER OF REPETITIONS FOR MULTIUSERBROADCAST IN IOT DEPLOYMENTS”, docket number TPRO 00324 filed Jun. 7,2018, all of which are assigned to the assignee hereof and herebyexpressly incorporated by reference in their entirety.

FIELD

This invention generally relates to wireless communications and moreparticularly to relaying signals between wireless communicationstations.

BACKGROUND

The Internet of things (IoT) is the extension of Internet connectivityinto physical devices and everyday objects. Embedded with electronics,Internet connectivity, and other forms of hardware (e.g., such assensors), IoT devices can (1) communicate and interact with otherdevices over the Internet, and (2) be remotely monitored and controlled.The definition of IoT has evolved due to the convergence of multipletechnologies, real-time analytics, machine learning, commodity sensors,and embedded systems. Traditional fields of embedded systems, wirelesssensor networks, control systems, automation (including home andbuilding automation), and others all contribute to enabling the Internetof things.

In some cases, IoT devices operate in deep coverage areas where thedownlink received signal strength is very poor. In extreme scenarios,the received signal strength at the IoT device receiver could have asignal-to-noise ratio (SNR) as low as SNR=−14 dB. In such situations,relay nodes are deployed for transmissions to the hard-to-reach IoTdevices. However, the relay nodes improve the received signal strengthat the expense of higher complexity. The increase in complexity is aresult of interference management (e.g., in-band relays) and the controlsignaling required to manage the base station-relay node downlinktransmission and scheduling of the relay node-IoT device links.

SUMMARY

A relay node receives a data block containing multiplexed data streamsintended for multiple user equipment (UE) devices being served by therelay node. The relay node extracts the data streams from the data blockand allocates them each to a separate narrowband channel that isassociated with a particular UE device. The relay node repeatedlytransmits the narrowband channels to the UE devices in a broadcasttransmission that is transmitted for a predetermined number ofrepetitions. Each UE device decodes their own respective narrowbandchannel to obtain the data stream intended for the UE device associatedwith a particular narrowband channel. A feedback mechanism is utilizedby the relay node to determine whether to retransmit a data packet or anew data packet in subsequent broadcast transmissions.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a communication system for an example inwhich a relay node is used to broadcast data streams to a plurality ofuser equipment (UE) devices.

FIG. 2A is a block diagram of an example of the base station shown inFIG. 1.

FIG. 2B is a block diagram of an example of the relay node shown in FIG.1.

FIG. 2C is a block diagram of an example of the UE devices shown in FIG.1.

FIG. 2D is a block diagram of an example of the circuitry utilizedwithin the relay node shown in FIG. 1.

FIG. 3 is a messaging diagram of an example of the messages exchangedbetween the relay node and UE devices when determining a predeterminednumber of repetitions to transmit the broadcast transmission to the UEdevices.

FIG. 4 is a block diagram of an example of a data packet with embeddedfeedback process information.

FIG. 5 is a messaging diagram of an example of the messages exchangedbetween the relay node and UE devices when utilizing a defaultpredetermined number of repetitions to transmit the broadcasttransmission to the UE devices.

FIG. 6 is a flowchart of an example of a method in which a relay nodeuses control information to extract, from a block of data, a data streamfor each of a plurality of UE devices and transmits, to the plurality ofUE devices via a broadcast transmission, the data stream for each of theplurality of UE devices.

FIG. 7 is a flowchart of an example of a method in which a relay noderepeatedly transmits, for a predetermined number of repetitions, abroadcast transmission to a plurality of UE devices. The broadcasttransmission includes a data stream for each of the plurality of UEdevices.

FIG. 8 is a flowchart of an example of a method in which a relay nodetransmits control information to a plurality of UE devices andtransmits, to the plurality of UE devices via a broadcast transmission,a data stream for each of the plurality of UE devices.

FIG. 9 is a flowchart of an example of a method in which a relay nodetransmits a broadcast transmission to a plurality of UE devices andreceives a feedback message from each of the plurality of UE devicesregarding their respective data streams.

DETAILED DESCRIPTION

The examples described herein utilize a Multiuser Broadcast Transmission(MBT) to serve the IoT devices. For example, a small cell node (e.g.,relay node) uses MBT to transmit data to the IoT devices that are out ofthe reach of a macrocell node (e.g., base station). The MBT is a singlebroadcast transmission to a plurality of user equipment (UE) devicesthat contains data for each of the plurality of UE devices.

The MBT advantageously reduces the amount of control signaling requiredsince the relay node does not, in some examples, utilize anychannel-aware scheduling or channel quality feedback from the UE devicesfor the downlink transmissions. The reduced amount of control signalingand scheduler complexity results in a low-cost solution for both thesmall cell transmitter (e.g., relay node transmitter) and the UE devicereceivers. The small cell node performs Long-Term Evolution (LTE)Release-8 paging and IDLE mode procedures for the IoT UE devices such astransmitting the primary synchronization signal (PSS) and secondarysynchronization signal (SSS) channels, physical broadcast shared channel(PBSCH), Paging, and System Information Block (SIB) messaging.

In other examples, a UE device may act as a relay node for other UEdevices. The network (e.g., base station) may select the UE device thatacts as the relay node, or the UE device may volunteer to act as therelay node for other UE devices.

In still other examples, dual-connectivity (DC) could be used with themacrocell base station as the primary cell and the small cell node asthe secondary cell. In the DC example, the macrocell node (e.g., basestation) handles the basic paging and IDLE mode operations, and whenready, the UE devices switch to CONNECTED mode to transmit/receive dataon the secondary cell, which is provided by the small cell node.Although MBT is feasible in the DC mode, the majority of the examplesdescribed herein will refer to the small cell node as the relay node.

FIG. 1 is a block diagram of a communication system for an example inwhich a relay node is used to broadcast data streams to a plurality ofuser equipment (UE) devices. Communication system 100 is part of a radioaccess network (not shown) that provides various wireless services to UEdevices that are located within the respective service areas of thevarious base stations that are part of the radio access network. For theexamples herein, communication system 100 operates in accordance with atleast one revision of the 3rd Generation Partnership Project Long TermEvolution (3GPP LTE) communication specification.

In the interest of clarity and brevity, communication system 100 isshown as having only base station 102. However, in other examples,communication system 100 could have any suitable number of basestations. Base station 102, sometimes referred to as eNodeB or eNB,communicates with user equipment (UE) devices 106, 108, 110 via relaynode 104. For example, base station 102 transmits data to relay node 104via downlink signal 112, and relay node 104 broadcasts the data to UEdevices 106, 108, 110 via signal 114. UE devices 106, 108, 110 are anywireless communication devices such as a mobile phone, a transceivermodem, a personal digital assistant (PDA), or a tablet, for example.Although not explicitly shown in FIG. 1, base station 102 may alsoreceive uplink signals from relay node 104 and/or from UE devices 106,108, 110.

Base station 102 is connected to the network through a backhaul (notshown) in accordance with known techniques. As shown in FIG. 2A, basestation 102 comprises controller 204, transmitter 206, and receiver 208,as well as other electronics, hardware, and code. Base station 102 isany fixed, mobile, or portable equipment that performs the functionsdescribed herein. The various functions and operations of the blocksdescribed with reference to base station 102 may be implemented in anynumber of devices, circuits, or elements. Two or more of the functionalblocks may be integrated in a single device, and the functions describedas performed in any single device may be implemented over severaldevices.

For the example shown in FIG. 2A, base station 102 may be a fixed deviceor apparatus that is installed at a particular location at the time ofsystem deployment. Examples of such equipment include fixed basestations or fixed transceiver stations. In some situations, base station102 may be mobile equipment that is temporarily installed at aparticular location. Some examples of such equipment include mobiletransceiver stations that may include power generating equipment such aselectric generators, solar panels, and/or batteries. Larger and heavierversions of such equipment may be transported by trailer. In still othersituations, base station 102 may be a portable device that is not fixedto any particular location. Accordingly, base station 102 may be aportable user device such as a UE device in some circumstances.

Controller 204 includes any combination of hardware, software, and/orfirmware for executing the functions described herein as well asfacilitating the overall functionality of base station 102. An exampleof a suitable controller 204 includes code running on a microprocessoror processor arrangement connected to memory. Transmitter 206 includeselectronics configured to transmit wireless signals. In some situations,transmitter 206 may include multiple transmitters. Receiver 208 includeselectronics configured to receive wireless signals. In some situations,receiver 208 may include multiple receivers. Receiver 208 andtransmitter 206 receive and transmit signals, respectively, throughantenna 210. Antenna 210 may include separate transmit and receiveantennas. In some circumstances, antenna 210 may include multipletransmit and receive antennas.

Transmitter 206 and receiver 208 in the example of FIG. 2A perform radiofrequency (RF) processing including modulation and demodulation.Receiver 208, therefore, may include components such as low noiseamplifiers (LNAs) and filters. Transmitter 206 may include filters andamplifiers. Other components may include isolators, matching circuits,and other RF components. These components in combination or cooperationwith other components perform the base station functions. The requiredcomponents may depend on the particular functionality required by thebase station.

Transmitter 206 includes a modulator (not shown), and receiver 208includes a demodulator (not shown). The modulator modulates the signalsto be transmitted as part of the downlink signal 112 and can apply anyone of a plurality of modulation orders. The demodulator demodulates anyuplink signals received at base station 102 in accordance with one of aplurality of modulation orders.

As mentioned above, base station 102 provides various wireless servicesto UE devices 106, 108, 110 via relay node 104. For example, basestation 102 transmits data to relay node 104 via downlink signal 112,and relay node 104 broadcasts the data to UE devices 106, 108, 110 viasignal 114. The relay node 104 is sometimes referred to as a relay or asa small cell node.

As shown in FIG. 2B, relay node 104 comprises controller 216,transmitter 218, and receiver 214, as well as other electronics,hardware, and code. Relay node 104 is any fixed, mobile, or portableequipment that performs the functions described herein. The variousfunctions and operations of the blocks described with reference to relaynode 104 may be implemented in any number of devices, circuits, orelements. Two or more of the functional blocks may be integrated in asingle device, and the functions described as performed in any singledevice may be implemented over several devices.

For the example shown in FIG. 2B, relay node 104 may be a fixed deviceor apparatus that is installed at a particular location at the time ofsystem deployment. Examples of such equipment include fixed basestations or fixed transceiver stations. In some situations, relay node104 may be mobile equipment that is temporarily installed at aparticular location. Some examples of such equipment include mobiletransceiver stations that may include power generating equipment such aselectric generators, solar panels, and/or batteries. Larger and heavierversions of such equipment may be transported by trailer. In still othersituations, relay node 104 may be a portable device that is not fixed toany particular location. Accordingly, relay node 104 may be a portableuser device such as a UE device in some circumstances.

Controller 216 includes any combination of hardware, software, and/orfirmware for executing the functions described herein as well asfacilitating the overall functionality of relay node 104. An example ofa suitable controller 216 includes code running on a microprocessor orprocessor arrangement connected to memory. Transmitter 218 includeselectronics configured to transmit wireless signals. In some situations,transmitter 218 may include multiple transmitters. Receiver 214 includeselectronics configured to receive wireless signals. In some situations,receiver 214 may include multiple receivers. Receiver 214 andtransmitter 218 receive and transmit signals, respectively, throughantenna 212. Antenna 212 may include separate transmit and receiveantennas. In some circumstances, antenna 212 may include multipletransmit and receive antennas.

Transmitter 218 and receiver 214 in the example of FIG. 2B perform radiofrequency (RF) processing including modulation and demodulation.Receiver 214, therefore, may include components such as low noiseamplifiers (LNAs) and filters. Transmitter 218 may include filters andamplifiers. Other components may include isolators, matching circuits,and other RF components. These components in combination or cooperationwith other components perform the base station functions. The requiredcomponents may depend on the particular functionality required by thebase station.

Transmitter 218 includes a modulator (not shown), and receiver 214includes a demodulator (not shown). The modulator modulates the signalsto be transmitted as part of the broadcast signal 114 and can apply anyone of a plurality of modulation orders. The demodulator demodulates anyuplink signals received at relay node 104 in accordance with one of aplurality of modulation orders.

As shown in FIG. 2C, UE devices 106, 108, 110 utilize their respectiveantennas 220 and receivers 222 to receive downlink signals 114 fromrelay node 104. Besides antenna 220 and receiver 222, UE device 106(UE1) further comprises controller 224 and transmitter 226, as well asother electronics, hardware, and code. Although FIG. 2C specificallydepicts the circuitry and configuration of UE device 106, the same UEdevice circuitry and configuration is utilized for UE devices 108, 110in communication system 100. UE device 106 is any fixed, mobile, orportable equipment that performs the functions described herein. Thevarious functions and operations of the blocks described with referenceto UE device 106 may be implemented in any number of devices, circuits,or elements. Two or more of the functional blocks may be integrated in asingle device, and the functions described as performed in any singledevice may be implemented over several devices.

Controller 224 includes any combination of hardware, software, and/orfirmware for executing the functions described herein as well asfacilitating the overall functionality of a UE device. An example of asuitable controller 224 includes code running on a microprocessor orprocessor arrangement connected to memory. Transmitter 226 includeselectronics configured to transmit wireless signals. In some situations,the transmitter 226 may include multiple transmitters. Receiver 222includes electronics configured to receive wireless signals. In somesituations, receiver 222 may include multiple receivers. Receiver 222and transmitter 226 receive and transmit signals, respectively, throughantenna 220. Antenna 220 may include separate transmit and receiveantennas. In some circumstances, antenna 220 may include multipletransmit and receive antennas.

Transmitter 226 and receiver 222 in the example of FIG. 2C perform radiofrequency (RF) processing including modulation and demodulation.Receiver 222, therefore, may include components such as low noiseamplifiers (LNAs) and filters. Transmitter 226 may include filters andamplifiers. Other components may include isolators, matching circuits,and other RF components. These components in combination or cooperationwith other components perform the UE device functions. The requiredcomponents may depend on the particular functionality required by the UEdevice.

Transmitter 226 includes a modulator (not shown), and receiver 222includes a demodulator (not shown). The modulator can apply any one of aplurality of modulation orders to modulate the signals to be transmittedas uplink signals (not shown). The demodulator demodulates the downlinksignals 114 in accordance with one of a plurality of modulation orders.

In operation, base station 102 transmits, via transmitter 206 andantenna 210, downlink signal 112 to relay node 104. Downlink signal 112contains control information and a block of data assigned to UE devices106, 108, 110. In the example shown in FIG. 1, the block of dataincludes data intended for UE devices 106, 108, 110 that is multiplexed(e.g., combined) together to form a single signal 112. In some examples,the control information is a bitmap.

Relay node 104 receives downlink signal 112 via antenna 212 and receiver214. The control information helps relay node 104 identify UE devices106, 108, 110 and match them to their respective data streams. Morespecifically, relay node 104 uses the control information to (1) extractthe data stream for each of UE devices 106, 108, 110 from the block ofdata contained in downlink signal 112, and (2) assign each data streamto a narrowband channel, resulting in a frequency-division multiplexing(FDM)-based resource allocation.

For example, as shown in FIG. 2D, relay node 104 includes demultiplexer228, which is used in combination with receiver 214 of relay node 104and the control information received from base station 102, to (1)separate the multiplexed block of data contained in downlink signal 112into separate data streams intended for each of UE devices 106, 108,110, and (2) match each of the separated (e.g. extracted) data streamsto a particular UE device. As shown in FIG. 2D, the product ofdemultiplexer 228 is first data stream 230 that is matched to UE1 106,second data stream 232 that is matched to UE2 108, and third data stream234 that is matched to UE3 110. The functionality of demultiplexer 228is performed by controller 216 in the example shown in FIG. 2D. However,in other examples, the functionality of demultiplexer 228 may beperformed by any other suitable circuitry.

The separated data streams 230, 232, 234 are sent to resource mapper236, which maps (e.g., assigns) each of the separated data streams 230,232, 234 to a narrowband channel. In order to serve UE devices 106, 108,110, relay node 104 splits the downlink bandwidth of signal 114 into anumber of narrowband channels, for example, each consisting of sixresource blocks in the frequency domain, as specified in LTE-MachineType Communication (LTE-M) Release-12. In some examples, space-divisionmultiplexing (SDM) and/or frequency-hopping schemes on top of FDM can beapplied to each narrowband signal. In other examples, time-divisionmultiplexing (TDM) or code-division multiplexing (CDM) may be usedinstead of SDM. At the physical layer level, each UE-specific narrowbandchannel is allocated (e.g., assigned) a set of subcarriers within theportion of downlink channel bandwidth.

Relay node 104 transmits, via transmitter 218 and antenna 212, controlinformation to UE devices 106, 108, 110, which are configured to use thecontrol information to receive their respective data streams. In theexamples described herein, there are two methods to deliver the downlinkcontrol information (DCI) to UE devices 106, 108, 110. The DCIparameters common to all UE devices 106, 108, 110 are delivered usingthe Common Search Space Machine-Type Communication Physical DownlinkControl Channel (CSS-MPDCCH) or SIB messaging. The second method is tosend the DCI using the UE-specific search space (USS) MPDCCH or to embedthe DCI within a data packet in broadcast transmission 114.

The resource allocation (e.g., assignment) information, the modulationand coding scheme (MCS), and the transmission mode information for themultiuser broadcast transmission 114 are semi-static and can beannounced to all targeted UE devices 106, 108, 110 before beginning datatransmission since these parameters are kept the same during thetransmission of multiple data blocks. For example, after receiving theblock of data from base station 102 and determining N_(rep), relay node104 transmits control information regarding the resource assignmentinformation, the MCS, the N_(rep), and the transmission mode information(e.g., transmit diversity parameters, etc.) to UE devices 106, 108, and110 using the CSS-MPDCCH or SIB messaging.

As mentioned above, the control information transmitted to UE devices106, 108, 110 may include, for example, one or more of the following: apredetermined number of repetitions (e.g., times) that the broadcasttransmission 114 will be transmitted, a modulation and coding scheme,resource allocation (e.g., assignment) information, transmission modeinformation, and feedback process information. In some examples, thecontrol information is transmitted in a System Information Block (SIB)message. In other examples, the control information is transmitted on aCommon Search Space Machine-Type Communication Physical Downlink ControlChannel (CSS-MPDCCH). For example, UE devices 106, 108, 110 are informedabout the resource assignment information (e.g., which narrowbandchannel contains the data stream for which UE device and/or whichsubcarriers are associated with each narrowband channel) via controlinformation signaling (e.g. MPDCCH).

Once UE devices 106, 108, 110 are informed about the resource assignmentinformation and/or other control information, relay node 104 transmits abroadcast transmission 114 to UE devices 106, 108, 110 via transmitter218 and antenna 212. The broadcast transmission 114 contains the datastream for each of UE devices 106, 108, 110 in a separate narrowbandchannel. Although each of UE devices 106, 108, 110 will receive the samemultiuser broadcast transmission (MBT) 114 from relay node 104, each UEdevice 106, 108, 110 will use its own respective narrowband receiver,which may be integrated into receiver 222, to access (e.g., receive anddecode) the portion of the received downlink signal 114 that containsthe narrowband channel that has been assigned to that particular UEdevice.

To achieve robustness, relay node 104 transmits broadcast transmission114 for a predetermined number of repetitions using multi-subframerepetition, as defined in LTE-M Release-12. In IoT deployments, the datais repeatedly transmitted over multiple subframes to achieve robustnessat the expense of higher latency. In some examples, the predeterminednumber of repetitions is a default number of repetitions. In otherexamples, the predetermined number of repetitions is determined.

FIG. 3 is a messaging diagram of an example of the messages exchangedbetween relay node 104 and UE devices 106, 108, 110 when determining apredetermined number of repetitions, N_(rep), to transmit broadcasttransmission 114 to UE devices 106, 108, 110. In some examples, thepredetermined number of repetitions, N_(rep), is computed based on theworst received signal strength reported by UE devices 106, 108, 110. Asshown in FIG. 3, relay node 104 transmits, via transmitter 218 andantenna 212, paging message 302 to all UE devices 106, 108, 110 listedin the block of data received from base station 102. In the exampleshown in FIG. 3, relay node 104 uses the common search space (CSS)MPDCCH to page UE devices 106, 108, 110. In other examples, the UEdevices 106, 108, 110 periodically monitor the downlink signal 114 andmay receive data at a predetermined subframe (e.g., in polling schedulerdeployments).

In some examples, paging message 302 includes a request for UE devices106, 108, 110 to each submit downlink measurement reports to relay node104, based on their respectively measured received signal strength ofbroadcast transmission 114. In other examples, paging message 302includes a request for UE devices 106, 108, 110 to each submit downlinkmeasurement reports to relay node 104, if their received signal strengthmeasurement value

, is below a threshold value

_(t). In response to paging message 302, one or more of UE devices 106,108, 110 transmit their respective page response 304 using theirassigned Physical Uplink Control Channel (PUCCH) resources.

In some examples, one or more of the page responses 304 may include adownlink measurement report. In order to obtain exactness in someexamples, UE devices 106, 108, 110 include a quantized worseness of thereceived signal strength compared to one or more threshold values,

_(t), in the downlink measurement report. For example, if a UE device isexperiencing received signal strength below a first threshold value,

_(t1), then the UE device reports back a threshold index value of ‘1’,and if the received signal strength is below first and second thresholdvalues,

y_(t1) and

_(t2), then the UE device reports a threshold index value of ‘2’ and soon. Alternatively, if a UE device is experiencing received signalstrength up to 0.5 dB (e.g., within a first range) below

_(t), then the UE device reports back a range index value of ‘1’, and ifthe received signal strength is between 1 dB and 0.5 dB (e.g., within asecond range) below

_(t), then the UE device reports a range index value of ‘2’ and so on.

Thus, in light of the foregoing, the downlink measurement report mayinclude one or more of the following: a received signal strengthmeasurement value,

; a first threshold index value that indicates that a received signalstrength measurement value,

, is below a first threshold value; a second threshold index value thatindicates that a received signal strength measurement value,

, is below a first threshold value and a second threshold value; a firstrange index value that indicates that a received signal strengthmeasurement value,

, is within a first range of values below a first threshold value; and asecond range index value that indicates that a received signal strengthmeasurement value,

, is within a second range of values below a first threshold value.

Based on the number of UE devices 106, 108, 110 that report back thecondition

<

_(t) and their reported index value, relay node 104 utilizes controller216 to determine the value of N_(rep). With this approach, the value ofN_(rep) becomes a function of the number of UE devices 106, 108, 110reporting

<

_(t) and their respective reported index values.

After the value of N_(rep) is decided (e.g, by default or determined byrelay node 104), relay node 104 transmits control information 306 to beused for the multiuser broadcast transmissions 114 to all UE devices106, 108, 110. As mentioned above, this control information 306 mayinclude, for example, one or more of the following: a predeterminednumber of repetitions (e.g., N_(rep)) that the broadcast transmission114 will be transmitted, a modulation and coding scheme, resourceallocation (e.g., assignment) information, transmission modeinformation, and feedback process information. In some examples, thecontrol information is transmitted in a System Information Block (SIB)message. In other examples, the control information is transmitted on aCommon Search Space Machine-Type Communication Physical Downlink ControlChannel (CSS-MPDCCH). In still other examples, the control informationis transmitted in a data packet of broadcast transmission 114. Infurther examples, the control information is transmitted on aUE-specific Search Space Machine-Type Communication Physical DownlinkControl Channel (USS-MPDCCH). The resource allocation information andthe value of N_(rep) can be transmitted semi-statically to UE devices106, 108, 110 and are not required to be transmitted again until thereis a change in the resource allocation or the predetermined number ofrepetitions.

Regardless of the manner in which the predetermined number ofrepetitions is determined, relay node 104 transmits, via transmitter 218and antenna 212, broadcast transmission 114 (e.g., signal 308) for thepredetermined number of repetitions, N_(rep). UE devices 106, 108, 110utilize the control information 306 to receive the repeated broadcasttransmissions 114 and combine the energy received in each subframe toachieve a higher energy per bit, resulting in a higher successfuldetection rate. After receiving all N_(rep) subframes of data, each UEdevice 106, 108, 110 transmits feedback message 310 to relay node 104using a Physical Uplink Control Channel (PUCCH) or a Physical UplinkShared Channel (PUSCH). Relay node 104 receives feedback message 310 viaantenna 212 and receiver 214. In the example shown in FIG. 3, feedbackmessage 310 is either an ACK or a NACK signal.

In some examples, Hybrid Automatic Repeat Request (HARQ) feedback isused in connection with the multiuser broadcast transmissions 114 toachieve higher detection performance. To handle the HARQ processesassigned to a particular UE device, HARQ process information 404 such asa HARQ Process Identifier (ID) (HPI), a New Data Indicator (NDI), and aRedundancy Version (RV) is embedded in the data packet 402 itself, asshown in FIG. 4. After receiving the narrowband channel data packet,each UE device 106, 108, 110 decodes the HARQ process information 404before decoding the data in the data packet 402. This allows each UEdevice 106, 108, 110 to monitor and track its own respective HARQprocess information.

In some examples, the UE device waits to receive all the repetitions(e.g., N_(rep)) of the broadcast transmission 114 before attempting todecode the packet. In other examples, the UE device may attempt todecode the packet after receiving any number of repetitions or afterreceiving each repetition. Depending on the decoding success, the UEdevice sends either an ACK or a NACK feedback message to relay node 104.If the UE device is successfully able to decode the packet beforereceiving all of the repetitions, the UE device could send an earlytermination ACK. If the feedback message is an ACK, relay node 104transmits a new data packet (and a New Data Indicator) in the nexttransmission. If the feedback message is a NACK, relay node 104transmits a next Redundancy Version packet (and an associated RedundancyVersion (RV) value) in the next transmission. As a consequence of usingthis HARQ process for different UE devices 106, 108, 110 within the samemultiuser broadcast transmission 114, the RV of the data packetsaddressed to different UE devices 106, 108, 110 could be different.Thus, relay node 104 is responsible for managing the HARQ processes foreach of UE devices 106, 108, 110.

Since multiple UE devices 106, 108, 110 are served with the multiuserbroadcast transmission 114, the PUCCH capacity may not be enough totransmit the large number of ACK/NACK feedback messages. Thus, in someexamples, UE devices 106, 108, 110 are allowed to transmit theirACK/NACK feedback messages on PUSCH resources. In some examples, theamount of feedback signaling can be reduced if the UE devices 106, 108,110 only transmit a NACK if they are unable to decode the data packetafter receiving all of the repetitions (e.g., N_(rep)).

FIG. 5 shows the signaling flows when a default MCS and a defaultN_(rep) are used for the multiuser broadcast transmission 114. The useof a default MCS and a default N_(rep) for the multiuser broadcasttransmission 114 reduces the amount of control signaling required. Forexample, relay node 104 announces the default MCS value and the defaultN_(rep) value periodically to all UE devices 106, 108, 110 using SIBmessaging (e.g., control information 502). After the block of data isreceived from base station 102, relay node 104 allocates (e.g., assigns)the narrowband channels to UE devices 106, 108, 110 and transmits thoseassignments to the respective UE devices 106, 108, 110 in the pagemessages 504 transmitted to UE devices 106, 108, 110. UE devices 106,108, 110 transmit page responses 506 on granted PUSCH resources. Inother examples, the page messages 504 are not required if UE devices106, 108, 110 are already periodically scheduled (e.g., by a pollingscheduler) to monitor the data channel 114 to receive the narrowbandchannel assignments.

Relay node 104 transmits broadcast transmission 508 for the defaultnumber of repetitions, N_(rep). UE devices 106, 108, 110 transmitfeedback messages 514 to relay node 104 on granted PUSCH resources.Based on the received feedback messages 514, relay node 104 placeseither a new data packet or a next Redundancy Version packet on theassigned narrowband channel for each UE device 106, 108, 110. Unless oneor more UE devices 106, 108, 110 report back a worse channel condition

<

_(t), relay node 104 avoids transmitting the MPDCCH. The MPDCCH is onlytransmitted to provide the new non-default values of the MCS and/orN_(rep).

There are several advantages to the examples described herein. Forexample, as mentioned above, the examples described herein do notrequire a complex channel-aware scheduler and do not require frequentindividual Channel State Information (CSI) feedback from the UE devices106, 108, 110. This significantly reduces the complexity of relay node104 and reduces the control signaling overhead. In addition, themultiuser broadcast transmissions 114 from the near-located relay node104 allow for a reduced number of required repetitions, N_(rep),achieving further efficiency.

FIG. 6 is a flowchart of an example of a method in which a relay nodeuses control information to extract, from a block of data, a data streamfor each of a plurality of UE devices and transmits, to the plurality ofUE devices via a broadcast transmission, the data stream for each of theplurality of UE devices. The method 600 begins at step 602 withreceiving, at relay node 104, a block of data and control information.At step 604, relay node 104 uses the control information to extract adata stream, from the block of data, for each of UE devices 106, 108,110. At step 606, relay node 104 assigns each data stream to one of aplurality of narrowband channels. At step 608, relay node 104 allocatesa set of subcarriers to each of the plurality of narrowband channels. Atstep 610, relay node 104 transmits, to UE devices 106, 108, 110,resource assignment information. At step 612, relay node 104 transmits,to UE devices 106, 108, 110, a paging message. At step 614, relay node104 transmits, to UE devices 106, 108, 110 via a broadcast transmission114, the data stream for each of UE devices 106, 108, 110.

FIG. 7 is a flowchart of an example of a method in which a relay noderepeatedly transmits, for a predetermined number of repetitions, abroadcast transmission to a plurality of UE devices. The broadcasttransmission includes a data stream for each of the plurality of UEdevices. The method 700 begins at step 702 with transmitting controlinformation from relay node 104 to UE devices 106, 108, 110. At step704, relay node 104 transmits a paging message to UE devices 106, 108,110. At step 706, relay node 104 receives at least one downlinkmeasurement report from at least one of UE devices 106, 108, 110. Atstep 708, relay node 104 determines a predetermined number ofrepetitions based on at least one downlink measurement report. At step710, relay node 104 repeatedly transmits, for the predetermined numberof repetitions, a broadcast transmission 114 to UE devices 106, 108,110. The broadcast transmission 114 includes a data stream for each ofUE devices 106, 108, 110.

FIG. 8 is a flowchart of an example of a method in which a relay nodetransmits control information to a plurality of UE devices andtransmits, to the plurality of UE devices via a broadcast transmission,a data stream for each of the plurality of UE devices. The method 800begins at step 802 with receiving, at relay node 104, a block of datacontaining a data stream for each of UE devices 106, 108, 110. At step804, relay node 104 assigns each data stream to one of a plurality ofnarrowband channels. At step 806, relay node 104 allocates a set ofsubcarriers to each of the plurality of narrowband channels. At step808, relay node 104 transmits control information to UE devices 106,108, 110. At step 810, relay node 104 transmits a broadcast transmission114 to UE devices 106, 108, 110. The broadcast transmission 114 includesa data stream for each of UE devices 106, 108, 110.

FIG. 9 is a flowchart of an example of a method in which a relay nodetransmits a broadcast transmission to a plurality of UE devices andreceives a feedback message from each of the plurality of UE devicesregarding their respective data streams. The method 900 begins at step902 with transmitting control information from relay node 104 to UEdevices 106, 108, 110. At step 904, relay node 104 transmits a broadcasttransmission 114 to UE devices 106, 108, 110. The broadcast transmission114 includes a data stream for each of UE devices 106, 108, 110. At step906, relay node 104 receives a feedback message from each of UE devices106, 108, 110 regarding their respective data streams. At step 908, ifthe feedback message is an ACK signal, relay node 104 transmits a newdata packet in the next transmission to the UE device that sent the ACKsignal. At step 910, if the feedback message is a NACK signal, relaynode 104 transmits a next Redundancy Version data packet in the nexttransmission to the UE device that sent the NACK signal.

Clearly, other embodiments and modifications of this invention willoccur readily to those of ordinary skill in the art in view of theseteachings. The above description is illustrative and not restrictive.This invention is to be limited only by the following claims, whichinclude all such embodiments and modifications when viewed inconjunction with the above specification and accompanying drawings. Thescope of the invention should, therefore, be determined not withreference to the above description, but instead should be determinedwith reference to the appended claims along with their full scope ofequivalents.

1. A method comprising: transmitting control information from a relaynode to a plurality of user equipment (UE) devices; and repeatedlytransmitting, for a predetermined number of repetitions, a broadcasttransmission from the relay node to the plurality of UE devices, thebroadcast transmission including a data stream for each of the pluralityof UE devices, each of the plurality of UE devices configured to use thecontrol information to receive their respective data streams.
 2. Themethod of claim 1, wherein the control information comprises at leastone of the following: the predetermined number of repetitions, amodulation and coding scheme, resource allocation information,transmission mode information, and feedback process information.
 3. Themethod of claim 1, wherein transmitting control information comprises atleast one of the following: transmitting control information in a SystemInformation Block (SIB) message, and transmitting control information ona Common Search Space Machine-Type Communication Physical DownlinkControl Channel (CSS-MPDCCH).
 4. The method of claim 1, wherein thepredetermined number of repetitions is a default number of repetitions.5. The method of claim 1, further comprising: determining thepredetermined number of repetitions.
 6. The method of claim 5, furthercomprising: receiving at least one downlink measurement report from atleast one of the plurality of UE devices; and determining thepredetermined number of repetitions based on the at least one downlinkmeasurement report.
 7. The method of claim 6, wherein the at least onedownlink measurement report comprises: a first index value thatindicates that a received signal strength measurement value is below afirst threshold value.
 8. The method of claim 6, wherein the at leastone downlink measurement report comprises: a second index value thatindicates that a received signal strength measurement value is below afirst threshold value and below a second threshold value.
 9. The methodof claim 5, further comprising: transmitting a paging message to theplurality of UE devices; and receiving at least one downlink measurementreport from at least one of the plurality of UE devices, the at leastone downlink measurement report being transmitted in response to thepaging message.
 10. The method of claim 9, wherein the paging messageincludes a request for the at least one downlink measurement report if areceived signal strength measurement value is below a first thresholdvalue.
 11. A relay node comprising: a transmitter configured to:transmit control information to a plurality of user equipment (UE)devices; and repeatedly transmit, for a predetermined number ofrepetitions, a broadcast transmission to the plurality of UE devices,the broadcast transmission including a data stream for each of theplurality of UE devices, each of the plurality of UE devices configuredto use the control information to receive their respective data streams.12. The relay node of claim 11, wherein the control informationcomprises at least one of the following: the predetermined number ofrepetitions, a modulation and coding scheme, resource allocationinformation, transmission mode information, and feedback processinformation.
 13. The relay node of claim 11, wherein the transmitter isfurther configured to transmit control information in a SystemInformation Block (SIB) message.
 14. The relay node of claim 11, whereinthe transmitter is further configured to transmit control information ona Common Search Space Machine-Type Communication Physical DownlinkControl Channel (CSS-MPDCCH).
 15. The relay node of claim 11, whereinthe predetermined number of repetitions is a default number ofrepetitions.
 16. The relay node of claim 11, further comprising: acontroller configured to determine the predetermined number ofrepetitions.
 17. The relay node of claim 16, further comprising: areceiver configured to receive at least one downlink measurement reportfrom at least one of the plurality of UE devices, the controller furtherconfigured to determine the predetermined number of repetitions based onthe at least one downlink measurement report.
 18. The relay node ofclaim 17, wherein the at least one downlink measurement reportcomprises: a first index value that indicates that a received signalstrength measurement value is below a first threshold value.
 19. Therelay node of claim 17, wherein the at least one downlink measurementreport comprises: a second index value that indicates that a receivedsignal strength measurement value is below a first threshold value andbelow a second threshold value.
 20. The relay node of claim 16, whereinthe transmitter is further configured to transmit a paging message tothe plurality of UE devices, the relay node further comprising: areceiver configured to receive at least one downlink measurement reportfrom at least one of the plurality of UE devices, the at least onedownlink measurement report being transmitted in response to the pagingmessage.
 21. The relay node of claim 20, wherein the paging messageincludes a request for the at least one downlink measurement report if areceived signal strength measurement value is below a first thresholdvalue.